We propose a comprehensive evaluation of the reported association between periodontal infections and myocardial infarction. Periodontal diseases, which are caused by bacteria and associated with increased prevalence and severity of bacteremia, may represent significant, previously unrecognized risk for coronary artery disease. The bacteremias associated with periodontal infections often involve bacteria with the ability to aggregate platelets and stimulate cells involved in atheromatous plaque formation. Hence, frequent bacteremia with subgingival plaque bacteria may increase the chances of thromboembolic events leading to myocardial infarction. Our specific aims include: 1) To evaluate the association between myocardial infarction and infectious periodontal disease in a population based case-control study, and 2) To evaluate the association between myocardial infarction and the subgingival microflora associated with infectious periodontitis including organisms such as S. sanguis and P. gingivalis which express platelet associated aggregation protein. The dependent variable, or outcome of interest, will be documented non-fatal myocardial infarction in approximately 960 cases, 35 to 69 years of age, compared to 2200 age-matched controls. Cases and controls will include blacks and whites of both genders who are being assembled at the University at Buffalo for a study of myocardial infarction and alcohol consumption. We propose adding an oral health component to this funded study, clarifying the relationship between the exposures of interest, destructive periodontitis and the subgingival microflora, and coronary artery disease, specifically myocardial infarction. We will systematically evaluate the role of multiple confounders and co-risk factors such as smoking, age, diet, and alcohol use. The proposed study will help clarify the relationship between periodontal disease and myocardial infarction. Detailed evaluation of the potential of chronic infections such as periodontal disease to contribute to the risk of myocardial infarction is important, since cardiovascular disease remains a leading cause of death in most developed countries. Furthermore, periodontal disease is one of the most common infections of man. Therefore, understanding the association between these two diseases is of significant importance, both to individuals and for public health measures directed to reducing their morbidity and mortality.